1. Field of the Invention
The present invention relates to an edge emitting LED (light emitting diode) and a fabrication method, paticuraly to an edge emitting LED having a selective-area growth optical absorption region.
2. Description of the Related Art
FIG. 6 is perspective cross sectional view showing a light emitting diode in accordance with the prior art.
Referring to FIG. 6, a prior art edge-emitting LED comprises a p-InP substrate 1, an n-InP block layer 2, a p-InP block layer 3, a p-InP cladding layer 4, active layers 5, 8, a p-InGaAsP light emitting region A, an n-InGaAsP contact layer 7, a p-InGaAsP optical absorption region B, and an SiO2 film 9.
The prior art edge emitting LED has an optical absorption region B separated from the light emitting region A and the InP block layer 6.
A backward light emitted in the light emitting region A is propagated to the InP block layer 6 with some radiation angles due to diffraction, through the optical absorption region B.
Then, the backward light combines with the optical absorption region B. Since an effective bandgap of the optical absorption region B is smaller than that of the light emitting region A, the light combined with the optical absorption region B decreases due to an optical absorption effect.
As a result, a very small amount light can reach to the back facets of the optical absorption region B and optical feedback to the light emitting region A can be avoided.